This invention relates to a sheet discharge control method, a sheet discharge apparatus and an image forming apparatus for stacking sheets with images formed thereon discharged from an image forming apparatus such as a copier or a printer.
Conventionally, a sheet discharge apparatus that stacks sheets with images formed thereon by an image forming apparatus such as a copier or a printer onto a stacking tray has been well known.
In the sheet discharge apparatus, if a sheet is removed from the stacking tray while the apparatus is operating and continuously discharging sheets, the sheets will not be stacked on the stacking tray at a specific position in an aligned state.
For this reason, in Japanese Patent Publication (Tokkai) No. 63-247267, a sheet finishing apparatus includes a sheet stacking device moving relative to a sheet discharging unit for stacking the sheets, a detection device for detecting whether a sheet is removed from the sheet stacking device, and a control device for temporarily stopping the sheet discharge unit from discharging the sheets according to an output of the detection device.
In this sheet finishing apparatus, if the sheets are already fed to a recording unit or a transport unit in the image forming apparatus when the sheet is removed from the stacking tray, the sheets will jam in the image forming apparatus such as a copier or a printer by temporarily stopping the discharge operation of the sheet finishing apparatus.
In the type of technology described above, problems regarding the poor sheet alignment and the discharging performance exist. According to this technology, when the sheet is removed and the discharging operation of the sheet finishing apparatus is temporarily stopped, the image forming apparatus such as a copier or a printer may have a sheet jam or a folded sheet, and thus have a poor discharge performance.
An objective of the present invention is to solve the problems associated with the conventional technology and to provide a sheet discharge control method, a sheet discharge apparatus, an image forming apparatus and a program that eliminate the sheet jam or the folded sheet in the image forming apparatus or the sheet discharge apparatus (including a sheet finishing apparatuses) and improve the alignment of the sheets and the discharging performance.
In order to attain the aforementioned objective, according to the present invention, a sheet discharge apparatus is equipped with discharge means for discharging sheets from an image forming apparatus, storage means for storing the sheets discharged from the aforementioned discharge means; elevator means for raising and lowering the aforementioned storage means relative to the aforementioned discharge means; position detection means for detecting a surface of the upper most sheet stored in the aforementioned storage means or a surface of the aforementioned storage means on which the sheet is to be stacked; reception means for receiving a signal from the aforementioned image forming apparatus indicating a sheet transport status in the aforementioned image forming apparatus; and control means for temporarily stopping the aforementioned discharge means when the aforementioned position detection means detects the upper most surface of the sheets stored on the aforementioned storage means or the surface of the aforementioned storage means for stacking the sheets to be away from a predetermined position and the aforementioned reception means detects the sheet is being transported in the aforementioned image forming apparatus, after the sheet being transported is discharged to the aforementioned storage means by the aforementioned discharge means.
In the sheet discharge apparatus according to the present invention, the control means controls the aforementioned elevator means to move the aforementioned storage means back to the aforementioned predetermined position while the aforementioned discharge means is temporarily stopped discharging the sheets.
Also, according to the sheet discharge apparatus of the present invention, the aforementioned control means starts a drive of the aforementioned elevator means during a period of time between when the aforementioned reception means detects the sheet being transported exists in the aforementioned image forming apparatus and when the aforementioned discharge means discharges the sheet to the aforementioned storage means, and controls the aforementioned elevator means to move the aforementioned storage means to a predetermined position.
The sheet discharge apparatus according to the present invention may be further equipped with sheet size reception means for receiving a signal from the aforementioned image forming apparatus indicating a size of the sheet being transported in the aforementioned image forming apparatus, and the aforementioned control means controls a timing to start the aforementioned elevator means according to the size of the sheet received by the aforementioned sheet size reception means.
The control means in the sheet discharge apparatus according to the present invention controls the aforementioned elevator means to start the drive earlier as the size of the sheets received by the aforementioned sheet size reception means becomes smaller.
The sheet discharge apparatus according to the present invention may be further equipped with sheet length reception means for receiving a signal from the aforementioned image forming apparatus indicating the length of the sheets being transported in a transport direction in the aforementioned image forming apparatus, and the aforementioned control means controls a timing to start the aforementioned elevator means according to the length of the sheet in the transport direction received by the aforementioned sheet length reception means.
The control means in the sheet discharge apparatus according to the present invention controls the aforementioned elevator means to start a drive thereof earlier as the length of the sheets in the transport direction received by the aforementioned sheet length reception means becomes shorter.
The sheet discharge apparatus according to the present invention may be further equipped with sheet size reception means for receiving a signal from the aforementioned image forming apparatus indicating the size of the sheet being transported in the aforementioned image forming apparatus, and the aforementioned control means controls the aforementioned elevator means to change an elevating speed of the aforementioned storage means according to the size of the sheet received by the aforementioned sheet size reception means.
The control means in the sheet discharge apparatus according to the present invention controls the aforementioned storage means to increase a rising and lowering speed of the aforementioned elevator means as the size of the sheets received by the aforementioned sheet size reception means becomes smaller.
The sheet discharge apparatus according to the present invention may be further equipped with sheet length reception means for receiving a signal from the aforementioned image forming apparatus indicating the length of the sheet being transported in the transport direction in the aforementioned image forming apparatus, and the aforementioned control means controls the aforementioned elevator means to change a rising and lowering speed of the aforementioned storage means according to the length of the sheet in the transport direction received by the aforementioned sheet length reception means.
The control means in the sheet discharge apparatus according to the present invention controls the aforementioned elevator means to increase the elevating speed of the aforementioned storage means earlier as the length of the sheets in the transport direction received by the aforementioned sheet length reception means becomes shorter.
The sheet discharge apparatus according to the present invention may be further equipped with support means for supporting the sheets discharged by the aforementioned discharge means, and further equipped with finishing means for finishing the sheets while straddling between the aforementioned support means and the aforementioned storage means.
The sheet discharge apparatus according to the present invention performs alignment, binding or opening hole on the sheets as the aforementioned finishing means.
An image forming apparatus according to the present invention comprises stacking means for stacking the sheets; sheet supply means for supply the sheets from the aforementioned stacking means one sheet at a time; image forming means for forming an image onto the sheet supplied from the aforementioned sheet supply means; storage means for storing the sheets with the image formed thereon by the aforementioned image forming means; a transport path for guiding the sheet from the aforementioned image forming means to the aforementioned storage means; transport means for transporting the sheet along the aforementioned transport path and storing the sheet in the aforementioned storage means; sheet presence detecting means for detecting a presence of the sheet in the aforementioned transport path; elevator means for raising and lowering the aforementioned storage means relative to a downstream end of the aforementioned transport means in the sheet transport direction, position detection means for detecting the uppermost surface of the sheets stored in the aforementioned storage means or a surface of the aforementioned storage means for stacking the sheets; and control means for temporarily stopping the aforementioned sheet supply means when the aforementioned position detection means detects that the uppermost surface of the sheets stored in the aforementioned storage means or the surface of the aforementioned storage means for stacking the sheets are away from a predetermined position and the aforementioned sheet presence detection means detects the sheet in the aforementioned transport path, after the aforementioned sheet being transported is stored in the aforementioned storage means.
According to the present invention, a sheet discharge apparatus is equipped with discharge means for discharging sheets from an image forming apparatus; storage means for storing the sheets discharged from the aforementioned discharge means; elevator means for raising and lowering the aforementioned storage means relative to the aforementioned discharge means; position detection means for detecting a surface of the upper most sheet stored in the aforementioned storage means or a surface of the aforementioned storage means on which the sheet is to be stacked; and control means for temporarily stopping the aforementioned discharge means when the aforementioned position detection means detects the upper most surface of the sheets stored on the aforementioned storage means or the surface of the aforementioned storage means for stacking the sheets to be away from a predetermined position and the aforementioned reception means detects the sheet is being transported in the aforementioned image forming apparatus, after the sheet being transported is discharged to the aforementioned storage means by the aforementioned discharge means.
The sheet discharge apparatus according to the present invention may be further equipped with sheet size reception means for receiving a signal from the aforementioned image forming apparatus indicating a size of the sheet, and the aforementioned control means controls a timing to start the aforementioned elevator means according to the size of the sheet received by the aforementioned sheet size reception means.
The control means in the sheet discharge apparatus according to the present invention controls the aforementioned elevator means to start the drive earlier as the size of the sheets received by the aforementioned sheet size reception means becomes smaller.
The sheet discharge apparatus according to the present invention may be further equipped with sheet length reception means for receiving a signal from the aforementioned image forming apparatus indicating the length of the sheets in a transport direction, and the aforementioned control means controls a timing to start the aforementioned elevator means according to the length of the sheet in the transport direction received by the aforementioned sheet length reception means.
The control means in the sheet discharge apparatus according to the present invention controls the aforementioned elevator means to start a drive thereof earlier as the length of the sheets in the transport direction received by the aforementioned sheet length reception means becomes shorter.
The sheet discharge apparatus according to the present invention may be further equipped with sheet size reception means for receiving a signal from the aforementioned image forming apparatus indicating the size of the sheet, and the aforementioned control means controls the aforementioned elevator means to change an elevating speed of the aforementioned storage means according to the size of the sheet received by the aforementioned sheet size reception means.
The control means in the sheet discharge apparatus according to the present invention controls the aforementioned storage means to increase a rising and lowering speed of the aforementioned elevator means as the size of the sheets received by the aforementioned sheet size reception means becomes smaller.
The sheet discharge apparatus according to the present invention may be further equipped with sheet length reception means for receiving a signal from the aforementioned image forming apparatus indicating the length of the sheet in the transport direction, and the aforementioned control means controls the aforementioned elevator means to change a rising and lowering speed of the aforementioned storage means according to the length of the sheet in the transport direction received by the aforementioned sheet length reception means.
The control means in the sheet discharge apparatus according to the present invention controls the aforementioned elevator means to increase the elevating speed of the aforementioned storage means earlier as the length of the sheets in the transport direction received by the aforementioned sheet length reception means becomes shorter.
The structures of the present invention described above effectively eliminate a sheet jam and a folded sheet in the image forming apparatus or the sheet discharge apparatus (the sheet finishing apparatus) to improve the alignment of the discharged sheets and the discharging performance.